The Documentation/DMA-API-HOWTO.txt states that dma_map_sg returns the
numer of the created entries in the DMA address space. However the
subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg must be
called with the original number of entries passed to dma_map_sg. The
sg_table->nents in turn holds the result of the dma_map_sg call as stated
in include/linux/scatterlist.h. Adapt the code to obey those rules.Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com> --- For more information, see '[PATCH v2 00/21] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lkml.org/lkml/2020/5/4/373 --- drivers/media/platform/vsp1/vsp1_drm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/media/platform/vsp1/vsp1_drm.c b/drivers/media/platform/vsp1/vsp1_drm.c index a4a45d6..b54a30f 100644 --- a/drivers/media/platform/vsp1/vsp1_drm.c +++ b/drivers/media/platform/vsp1/vsp1_drm.c @@ -912,8 +912,9 @@ int vsp1_du_map_sg(struct device *dev, struct sg_table *sgt) * skip cache sync. This will need to be revisited when support for * non-coherent buffers will be added to the DU driver. */ - return dma_map_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, - DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + sgt->nents = dma_map_sg_attrs(vsp1->bus_master, sgt->sgl, + sgt->orig_nents, DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + return sgt->nents; } EXPORT_SYMBOL_GPL(vsp1_du_map_sg); @@ -921,7 +922,7 @@ void vsp1_du_unmap_sg(struct device *dev, struct sg_table *sgt) { struct vsp1_device *vsp1 = dev_get_drvdata(dev); - dma_unmap_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, + dma_unmap_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->orig_nents, DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL_GPL(vsp1_du_unmap_sg); -- 1.9.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
